Slow-to-release relay



22, 1933- E. FRISCHKNECHT 1,923,363

SLOW- TO-RELEASE RELAY FiledApril 9, 1930 u/ahd, f

fi/Ls ATTORNEYS Patented Aug. 22, 1933 SLOW-TO-RELEASE RELAY ErnestFrischknecht, East Orange, N. .L, assignor to The TeleregisterCorporation, New York, N. Y., a Corporation ofDelaware Application April9,1930. Serial No. 442,975

2 Claims.

This invention relates to improvements in slow-to-release relays.

Among the objects of this invention is the provision of means forcausing a slow-to-release relay to pick up rapidly and to releasesubstantially within the same minimum time period regardless of thenumber of impulses sent over the coil of the relay.

Other objects of this invention will appear from the description takenin connection with the drawing inwhich the figure shows a controllingmeans for a slow-to-release relay, and an apparatus in which such arelay may be used.

For purposes of disclosure the drawing shows a plurality of indicators Aand B. The indicator A preferably comprises a ratchet wheel 1a, and anindicating pointer 2a secured to the ratchet wheel and which is adaptedto travel over indicating numerals as shown. The ratchet wheel 1a ispreferably operated by a pawl 3a actuated by a lever 4a operated by theoperating magnet 5a. The ratchet wheel and pointer may be returned tonormal by a spring 6a upon energization of a releasing magnet 7a whichdisengages the pawl So from the ratchet wheel 1a. The indicator B is ofthe same construction as the indicator A and corresponding partsof theindicator B are designated by the same numerals followed by smallletters 17.

For the purpose of selecting one of these indicators for operation aselecting device, such as shown at S, may be provided. This deviceincludes a ratchet wheel 18 and a circuit preparing arm 9 secured to theratchet wheel and which is 3 adapted to travel over an arcuate contactmember 10 to prepare a circuit from this contact member to one of thefixed contacts 11 to which the energizing leads 12a and 12b of theoperating magnets 5a and 5b of the indicators A and B are connected.This ratchet wheel is also operated by a pawl 38 which is actuated by anoperating magnet 58 and which may be disengaged from the ratchet wheelby energization of a releasing magnet 7s. [When the pawl is disengagedfrom the ratchet, the ratchet andv pointer are returned to normal homeposition by a spring 6s.

Secured also to the ratchet wheel ,8 is an arm 12 which when the ratchetwheel is moved out of home position releases the movable contact member14 to apply ground to a line 13.

For the purpose of transmitting a series of impulses a key 15 isprovided which connects battery over a constantly rotating interrupterl6 and over the coil of a relay 1'? to ground. At

the first impulse the relay 1'? picks up and closes a circuit at itsmake contact 18 from ground over a normal make and break contact 19 ofrelay 20 to the coil of the operating magnet 5s of 6 the selectingdevice S to battery and ground.

I interrupter.

The first impulse over the interrupter causes energization of theoperating magnet 58 which through the pawl 3s and ratchet 18 moves thearm 9 and the arm 12 ahead one step. As the.

arm 12 moves ahead one step it causes ground to be applied to the line13 over the contact member 14.

Energization of the relay 17 also applies ground at its make contact 18aover a non-in ductive resistance 21 and the'coil'of a s1ow-toreleaserelay 22 and over a normal break contact 23 of relay 24 to battery andground. The coil of the slOw-to-release relay '22 has a small number ofturns which causes the operating current for the sloW-to-release'relay22 to'build up very rapidly. Thisoauses the relay to be fast operating.The non indu'ctive resistance 21 r is inserted in this circuit toprevent the relay 22 from drawing too high a current. This resist- 7.in, in series with the coil of the slow-to-release relay'22 and thenon-inductive resistance 21. the slow-to-release relay 22 to drop'quickly. Preferably, the resistance 26 is such asto cause this drop 'incurrent to be effected. before the end of the first impulse overthe-coil of relay 22. The currentdropsbelow the operating re;

quirements and to a value -just sufficient to maintain theslow-to--release relay energized during the interval between impulsesover the Operation of this control is as follows I Asa single impulse orthe first of a series of impulses is sent over the non-inductiveresistance21 and thecoil of the slow-to-release relay 22 this relay willpick up very rapidly and because of its slow-to-release feature willremain operated until a subsequent impulse of a series of impulses istransmitted over its coil. The non-inductive'resistance 26 thrownin byenergization of the relay 24 will cut down the current over the coil ofthe relay 22 before the first impulse has ceased, to a minimum holdingvalue and thus permits the slow-to-release relay to release within acertain time period regardless of the number of impulses sent over itscoil. I Energization of the slow-to-release relay 22, opens its breakcontact 27 which disconnects ground that is applied to'the line 13by;the contact member 14 controlled bythe arm 12 as it moves out of itsreleased position and This causes the current. over. the coil of

